Plain English Meaning
Driving the airplane along the ground using its own engine to get to or from the runway.
Full Definition
The controlled movement of an airplane on the ground under its own power, typically between the parking area, runway, and other airport surfaces, using engine thrust for propulsion, rudder and nosewheel steering for directional control, and brakes for speed control and turning assistance.
Context Anchor
You encounter taxiing any time the airplane moves on the airport surface before takeoff or after landing.